Skimmer



NOV. 28, 1944. w. MCKEEN 2,363,885

SKIMMER Filed June 11, 1943 3 Sheets-Sheet 1 Nov. 28, 1944. H, w, MCKEEN2,363,885

SKIMMER Filed June 11,1943 3 Sheets-Sheet 2 Nov. 28, 1944. H w, MCKEIEN2,363,885

I SKIMME'R Filed June 11, 1943 3 Sheets-Sheet 3 9 TIE .5.-

i a j UNITED STATES ously in any preferred manner. purposes,aV-typepulliaw wis -shown-on one end Patented Nov.28, 1944 PAT- r maiSKIMMER: H em'y WL McKeen, Hurley, N. Mex.

, Applihation J une a 121,

it Cl'aiins.

In performing k-nownv material-separating processes, for example; theflotation processcf ore separation, frothor the like mustbecontinuouslyskimmed from the surface of a liq- 1 Ind, and the present invention aimst provide anew and improved skimmer for this purpose, possessingadvantages hereinafter explained.

With theforegoing in view, th invention resides in thenovelsubjectmatter hereinafter described and claimed, description being accomplishedby reference to' the accompanying drawings. Y

Figure- 1 is a front elevation, partly broken away and-in sectionshowing the" skimmer associated' with one of the cells of an oreseparating apparatus.

-; Figure 2 is a; vertical transverse sectional view orrline 22 ofFig. 1. l l t Figure 3 isa top-plan vi'ew. Figure 4 is afragmentarysectional view simi lar to a portion of Fig. 2' but showing the skimmercontrolling camtrack adjusted to a different position. l i

construction'has been disclosed whichis well adaptedfor carrying outthe" object of th invention and t-his construction will be ratherspeeifically described, with the understanding; however; that numerousvariations-within the realm of mechanicalskill; may be effected withinthe scope of the invention as' claimed. The disclosure is; therefore, tobe constructed as illustrative to a large extent ratherthanlimiting.

A tankorcell 5 has beenillustratedcontaining a liquid 6" from whichfrothyor the like I musthe continuously skimmed intoa launder 8. Theside walls 8 and, backwalllll of the cell 5 extend upwardly beyondtheliquid level and provide an open front enclosure for-'the skimmingmechanism, said side walls Nconstituting rigid supports for allpartswhich must be stationarily= mounted. i i

Bearings H are shownsecured to-theside walls 9, said bearingsrotat'ablysupporting a horizontal shaft [2, this shaft beingprovided'with two cross arms [3 near the side walls 9. One end of" each cross arm-l-3 extends" in the samedie rection from the shaft l'2a's* thecorresponding end of the other crossarm 1-3, and the other two ends ofsaid cross arms project in the-opposite direction from said shaft; thelatter being connected with the cross" arms at" their centers, wherebysaid shaft and cross arms constitute-a balanced rotatable member to bedriven continu- For illustrative 1943;;Serial Noa490g493 of said shaft:for engagement. with motor-driven belts (notshown). l l r Fourskimmer-carrying levers 14 are pivoted to the four ends of the crossarms I3 respeclevers It in the present: showing, said pivots beingparallel with the shaft [2 topermitlswinging of the levers l4 toward andfrom said shaft as said levers are carried along continuous paths by thecross arms l3: duringoperation of the machine. The levers- I4: carry askimmer l6 which, in the present disclosure, is :pivotall hung looselyfrom the outer ends of said levers, the pivots being shown at W. Eachskimmer l6 preferablv comprises an upper plate section It, a lower platesection F9 and awbolt-and-slot or equivalent adjustmentrlll.connectingsaid plate sections I18 and I9 for relative verticaladjustments. 20 pivots l1 and it will thus-be seen that the platesection I8 may be adjusted verticallywith re spect to said pivots tovary'the depth of skimming. v

The four levers I4 are: provided with lateral shoes 2| which arev shownlocated between the ends ofsaidlevers; said shoes being preferably inthe form of rollers; Cooperable with these shoes or rollers are two'continuous cam tracks 22 which control the pivotal movements of thelevers I4 with respect to the cross arms l3. during operation of themachine and, therefore, control the paths on which the Skimmers 16 move.Each cam trackway 22 includes an inclinedportion 23 which determines theline; upon which the' skimmer l6 will move during 'itsforward skimmingstroke. Each cam trackway also includes an arched portion 2'4 whichcontrols the lines onl which the skimmers move as theytravel.upwardly,,rearward1y and downwardly dur ing machineoperation, thelegs 25 01? the arched portion 24 being connected with the ends of theinclined portion 231. The two cam trackways 22 surround the shaft I 2and due to: this location The plate section 18 is secured: tovthe cell 5and terminates Well toward the front wall I of said cell, it being thusinsured that the Fig. 4. In order to accomplish this in a simple Jmanner, the elements 26 and 2'! used in construct-" ing the trackway 22have been shown secured by rivets 28 and 29, to a pair of verticalplates 39 lying against the cell side walls 9 and fastened to these sidewalls by means of bolts 3| which,

pass through mere bolt holes in said walls 9 but pass through slots 32in the plates 30, said slotsbeing concentric with the shaft [2 in thepresent disclosure. By loosening the bolts 3|, the two plates 30 and theelementsv 26 and 21 carried thereby, may be turned to the desiredposition and then looked in this position by retightening said bolts. Itwill thus be seen that the direction taken by the skimmers [6 inperforming their skimming strokes, may be varied as required. Attentionmay also be invited to the fact that this skimming stroke need not inall instancesbe on a straight line, as an upward and downward movementof the skimmer could be effected by suitably shaping the cam trackway22. l

Above, I refer to elements 26 and 21 used in forming the cam trackway22. Theseelements may be of any desired construction. For illustrativepurposes, element 26,is simply shown as a plate with its edgesuitablyshaped toform the inner wall of the trackway 22, and element 2.1is simply a distorted ring, for instance, of strap metal, suitablyshaped to constitute the other wall of said trackway In ore dressingflotation, it is recognized that t the mineral to be recovered issuspended on the surface of the bubble and that if the. bubbles arebrokemthe mineral precipitates. Itis, therefore,

desirable that the jfroth. be skimmed withthe least possible disturbanceof it. With my invention, the cam track can be shaped to cause theskimmer to enter the froth in a perpendicular position and withsubstantiallynoforward motion so that there is a minimum disturbance ofthe suspended elements contained in the cell. The cam tracks can alsocause the skimmer to move in a predetermined positive path and over.substantially the entire'area of the topof the cell.

That is a big improvement over prior skimmers of the type employing arotarypaddle at the discharge edge of the cell and also the typeemployingendless chains-with skimming paddles fixed to the chain links.In the latter type, the lower reaches of the chains sag and it is notpossible. to

- operate them so that skimming blades travel in-a in the water longenough to absorb water, and hence, there is a definite timeintervalindicated between skimming strokes. -This is possible only witha full-surface skimmer because the other.

.ment butalso the lackofdisturbance to the froth and the straightsagless path followed'by the;

skimmer blades, making it possible to skim at an exact predetermineddepth.

It will be noted that in my machine, all of the a friction bearingsurfaces are clear of the abrasive material in the feed since thetracks, arms and rollersare situated above and toward the ends of thecell away from the path followed by the skimmer blades or paddlesas theyreturn above the main shaft, thus preventing any-drippings cam guidewaysbe adjusted to change the direc-.

from coming in contact with such bearing sung faces.

for carrying out the object of the invention. The skimmers and theircarrying levers I4 remain retracted exceptjwhen needed, and as thelevers M of. either skimmer l6 more or lesscom-' plete a final downwardmovement, said levers are rearwardly projected toposition the skimmer l6close to the back wall it]. The skimmer then travels forwardly .on askimming stroke and at.

the completion of this stroke, the levers M are again retracted andtheyremain retracted until projection of them is again necessary..;The

skimming stroke extends, substantially overthe entire surface of theliquid, whereas most prior devices have skimmed only a small part of thesurfrace at or near the lip of the cell. The horizontal skimming motionor other skimming movement is imparted entirely by a steadily rotatingmechanism without the necessity of cranks, cross heads or rotating cams,which .is

decidedly advantageous in that. vibration is practically. eliminated andmaintenance is. kept at the minimum. The skimmers l6 remain suspended bygravity from their carrying levers l4 and 'do not become seriously,inclined even duringperformance of their skimming strokes, dueto thefact that the machine is slowly operated. This slow motion alsoovercomesor rather prevents injurious results which are often caused in othermechanisms by the action of centrifugal force at high speeds. Not only.may the tions of the lines on which the skimmers move, but as aboveexplained, it is possible to soconstruct said trackways that an up anddown movement of the skimmers could be attained during their skimmingstrokes, whether such up and down movements are uniform or not uniform.

Attention is again invite d to the possibility.

of making variations within the scope of themvention as claimed.

I claim g 1. A skimming device comprising a receptacle, a driven memberrotatably mounted on a horizontal axis above said receptacle, means forrotating said driven member, a skimmer carrying lever transverse to ;andspaced from said driven member, said pivot being radially spaced from,said axis, whereby said driven member will carry said lever upwardly,rearwardly, downskimmer carried by said lever and spaced from said pivotto perform a skimming operation at the surface of a liquidin saidreceptacle as said lever is carried forwardly, a lateral shoe on saidlever and spaced from said pivot, and a continuous stationary, cam trackengaging said shoe to control the pivotal movements of said lever withrespect tosaid driven member as said lever ,wardly, and forwardly on acontinuous path, a i r is carried along said continuous path, said camtrack havinga lower portion for determining the line of travel of saidskimmer during its forward skimming stroke, and other portions fordetermining the line of travel of said skimmer from each skimming stroketo the next.

2. A skimming device comprising a receptacle, a driven member rotatablymounted On a horizontal axis above said receptacle, means for rotatingsaid driven member, a skimmer-carrying lever transverselto and spacedfrom said axis,

a pivot connecting said lever with said driven member, said pivot beingradially spaced from said axis, whereby said driven member will carrysaid lever upwardly, rearwardly, downwardly,

and forwardly on a continuous path, a skimmer carried by said lever andspaced from said pivot to perform a skimmingoperation at the surface ofaliquid in said receptacle as said leveris carried forwardly, alateralshoe on said lever and spaced from said pivot, and a continuousstationary cam track engaging said shoe to control the pivotal movementsof said lever with respect to said driven memberas said lever is carriedalong said continuous path, said cam track having an inclined lowerportion for de,-

termining the line of travel of said skimmer during. its skimmingstroke, andan arched portion for determining the line of travel of saidskimmer from each skimming stroke to the next,

the legs of said arched portion being disposed in downwardly convergingrelation and connected with the ends of said inclined portion.

3. A structure as specified in claim 1; together with means adjustablymounting said cam track ,for shifting to a different position to .changesaidlines of travel of said skimmer.

l. A structure as specified in claim 1; together with means looselysuspending said skimmer i from said lever.

5. A skimming device comprising areceptacle, a horizontal driven, shaftrotatably mounted above said receptacle, means ,for rotating said drivenshaft, twospaced arms securedto and projecting radially in the samedirection from said shaft, two levers transverse to said shaft,

pivots connecting saidZlevers to said arms for swinging movement towardand from said shaft,

9. skimmer spaced from said shaft and extending between saidleversppivotal connections bee tween the ends of said skimmer and saidlevers and loosely suspending saidskimmer, said skimmer ,beinglocatedover said receptacle for skimming foam from a liquid in said receptacle,

lateralshoes on said levers and spaced from said shaft, and twocontinuousstationary camtracks surrounding said shaft and engaging saidshoes, to determine the pivotal movements of said levers with respect tosaid arms as the latter carry the levers upwardly, rearwardly,downwardly and forwardly, saidcam tracks having portions for determiningthe line of travel of said skimmer during its forward skimming stroke,and other portions for determining the line of travel of said skimmerfrom each skimming stroke to the next.

6. A structure as specified in claim 5; together with means adjustablymounting said cam tracks for movement to different positions to changesaid forward line of travel of said skimmer.

7. A structure as specified in claim 1; said skimmer having a verticallyadjustable lower section for varying the depth of skimming.

8. Astructureas specified in claim 5; said skimmer being composed of anupper plate section, a lower plate section and means connecting thesetwo plate sections for relative vertical, adjustment to vary thedepth ofskimming, the

aforesaid pivotal connections of the skimmer with said arms beingconnected withsaid upper plate section.

9. In a skimming mechanism, the combination of a cell, a supportassociated therewith, a

driven member rotatably mounted on a horizon tal axis above said cell,means for rotating said driven member, a lever pivoted to said member, i

a skimmer carried by said lever and located over said cell to perform askimming movement at the surface of a liquid in said cell, and a camtrack and shoe connection between said lever and I said support forswinging said lever with respect to said member and causing theskimmerto move in a predetermined path in its skimming movement oversaid cellwhen said member is rotated. 10. In a skimming mechanism, thecombination of a cell, a skimmer to perform a skimming movement oversaid cell, a skimmer-actuating means from which said skimmer ispivotally suspended for swinging movement with respect to saidskimmer-actuating means, said means ine eluding an endless cam track andcoacting shoe to travelaround said track to causethe skimmer in itsskimming movement and means for driv ing said skimmer-actuating meanstomove in a substantially perpendicular direction intothe froth in saidcell and to then move in a predeterminedpath through thefroth to the endof its skimming movement. j i

HENRY w. MCKEEN.

